Hydrodynamics of Collisions and Close Encounters between Stellar Black Holes and Main-sequence Stars
Persistent URL
Author(s)
Kremer, Kyle
Lombardi, James C., Jr. (Jamie)
Lu, Wenbin
Piro, Anthony L.
Rasio, Frederic A.
Date Issued
July 1, 2022
Abstract
Recent analyses have shown that close encounters between stars and stellar black holes occur frequently in dense star clusters. Depending upon the distance at closest approach, these interactions can lead to dissipating encounters such as tidal captures and disruptions, or direct physical collisions, all of which may be accompanied by bright electromagnetic transients. In this study, we perform a wide range of hydrodynamic simulations of close encounters between black holes and main-sequence stars that collectively cover the parameter space of interest, and we identify and classify the various possible outcomes. In the case of nearly head-on collisions, the star is completely disrupted with roughly half of the stellar material becoming bound to the black hole. For more distant encounters near the classical tidal-disruption radius, the star is only partially disrupted on the first pericenter passage. Depending upon the interaction details, the partially disrupted stellar remnant may be tidally captured by the black hole or become unbound (in some cases, receiving a sufficiently large impulsive kick from asymmetric mass loss to be ejected from its host cluster). In the former case, the star will undergo additional pericenter passages before ultimately being disrupted fully. Based on the properties of the material bound to the black hole at the end of our simulations (in particular, the total bound mass and angular momentum), we comment upon the expected accretion process and associated electromagnetic signatures that are likely to result.
Journal
Astrophysical Journal
Department
Physics
Citation
Kyle Kremer et al 2022 ApJ 933 203
Publisher
IOP Publishing Ltd
Version of Article
Published article
DOI
10.3847/1538-4357/ac714f
ISSN
0004-637X
1538-4357
Rights
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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